Pulmonary adenocarcinoma: review of 106 cases and proposed new classification.

The gross and microscopic appearances of 106 resected pulmonary adenocarcinomas were reviewed and correlated with postoperative survival. Instead of using an established classification based on histological pattern, the tumours were categorised by cellular morphology and site as either parenchymal adenocarcinoma (67%), bronchial adenocarcinoma (13%), or adenocarcinoma of uncertain origin (20%). Despite their pleomorphic appearance parenchymal adenocarcinomas should be regarded as a single entity, derived from multipotential cells of the distal airway; bronchial adenocarcinomas were generally, but not invariably, associated with short postoperative survival; those tumours that could not be reclassified on histological grounds were large adenocarcinomas consisting mainly of mucus cells. Tumours of this type carry a poor prognosis.